volcano

2. A lightweight volcanic rock filled with holes that can float on water.
5. Molten rock found beneath Earth's surface before it erupts.
8. A volcano that is currently inactive but may erupt again in the future.
10. A broad volcano with gentle slopes formed by thin, flowing lava.
12. The process in which magma, gases, and ash are released from a volcano.
14. A dark igneous rock commonly formed from lava flowing out of shield volcanoes.
16. A steep volcano made of alternating layers of lava and ash, also called a stratovolcano.
18. Molten rock that flows onto Earth's surface after an eruption.
19. An area where magma rises through the crust away from plate boundaries.
20. The belt around the Pacific Ocean where many earthquakes and volcanoes occur.

1. The process where one tectonic plate sinks beneath another, often creating volcanoes.
3. The bowl-shaped depression found at the top of many volcanoes.
4. Large pieces of Earth's lithosphere whose movement causes many volcanoes to form.
6. Tiny fragments of rock and volcanic glass blasted into the air during eruptions.
7. A large depression formed when a volcano collapses after a massive eruption.
9. The opening through which lava, ash, and gases escape during an eruption.
11. The underground reservoir where molten rock collects before an eruption.
13. A fast-moving mixture of hot gas, ash, and rock fragments that races down a volcano's slopes.
15. An opening in Earth's crust where magma, gases, and ash reach the surface.
17. The smallest type of volcano, built mainly from loose volcanic fragments.